is a hard time to be alive.
When I work 5-2 shifts, that's the absolute latest I can wake up and still make it on time. When the alarm goes off at 4:15 am, I have to lie very still in bed for a few minutes to make sure my heart is beating, moving life-giving blood to all my extremities before I try to go getting up. Several months ago I tried just hopping out of bed when the alarm went off at 4:15 am, and was painfully surprised to find that my heart had not actually begun beating yet, and the resultant zero blood pressure to my brain made me hit the ground like a sack of ground beef and jello. It was a good fifteen minutes before my heart could get over the shock and start beating again, I was late for work, covered in colourful bruises, and had to explain that I had, in fact, outrun my own body functions in trying to arise.
If you're worrying from a medical standpoint, don't--during the night my blood manages a sluggish, bayou-like movement through my veins via Brownian Movement, which gives me just enough circulation to keep the vital organs in a barely active state, while giving everything enough down-time to rest and revitalise. Several days of 4:15 am wakeups or one very fast exit from the bed at that time can and has done lasting damage to the system, but these mornings come rare enough that my brain has converted less vital areas of itself to help maintain the parts of my body that have been permanently devitalised by early morning jump starts. Extremely cold mornings, however, induce stupor like you have never seen.